In cases where a heat source (such as a power amplifier) must dissipate heat to a heat-sink or case on the opposite side of the printed circuit board (PCB), it is necessary to obtain a high thermal conductivity in the z-axis of the PCB. It is a common practice to drill and plate copper on an array of plated through-hole vias to thermally connect one side of the circuit board to the other. However, it is time consuming and often unreliable to plate copper on more than a small percentage of the hole. For this reason conductive fillers are often placed in the via. However, conductive filler typically makes a negligible contribution to overall thermal conductivity. Additionally, filling the via with a traditional solder has a low thermal conductivity and may also flow out during subsequent processing.